Abstract: An improved electron gun beam for a three color gun which has a central cathode and side cathodes mounted on either side of the central cathode which produce beams for different colors which pass through first and second grids and a main electron lens and wherein the first and second grids are generally conically shaped so that they extend toward the central cathode and have further indentations in their central portion which extend toward the central cathode and wherein the thickness of the second grid at the center wherein the beam of the central cathode passes therethrough is less than at the portions of the second grid where the beams from the two side cathodes pass therethrough and also where the distance between the central cathode and the indented portion of the first grid is larger than the distance between the two side cathodes and the distance to the first grid and/or the distance between the second and first grids is larger at the portion where the central cathode beam passes therethrough than wher

Abstract: An electron gun of uni-potential type is disclosed, which includes a main electron lens system consisting of a front electron lens system formed of a third grid and a fourth grid and a rear electron lens system formed of the fourth grid and a fifth grid of which the electron lens action regions are separated from each other. In this case, the electron lens diameter of the front electron lens system is selected smaller than that of the rear electron lens system, and the aperture diameter of the fifth grid in the rear electron lens system is selected larger than that of the fourth grid, and may be nearly as large as the inner diameter of the tube in which it is placed for use.